The number of electrical components in automotive vehicles have increased substantially in recent years. Trends suggest that the number and complexity of electrical components in vehicles will continue to increase. Many of the electrical components incorporated into automotive vehicles include a plurality of input/output signal carrying lines. For example, a typical automotive radio will include input/output lines extending to an illuminated radio dial, an electric clock incorporated into the radio dial and various power operated controls on the radio. The input/output lines for electrical components on a vehicle generally extend from a printed circuit board to an electrical connector having a plurality of terminals mounted therein. The leads extending from the circuit board to the connector are likely to generate or receive electrical interference, e.g., EMI/RFI. For example, the signals generated by an automotive radio may affect or be affected by other electronic components of the vehicle, such as CB radios, electronic fuel injection systems and electronic braking controls. Additionally, interference generated by electric components on one vehicle conceivably can affect the performance of electrical components on another vehicle. The effects of electrical interference on an automotive radio could be an annoying problem. On the other hand, the effects of electrical interference on an electronic fuel injection system or an electronic braking control could be catastrophic.
Most prior art vehicular radios and other electrical automotive components include capacitors, ferrite suppressors or other such filter means incorporated into the circuitry printed on the circuit board. Although these known suppressors and filters are effective to minimize interference generated on the circuit board, they are of limited effectiveness in filtering signals in the input/output lines leading to or extending from the circuit board. These signal lines external to the circuit board are now known to generate and/or receive a very significant portion of the electrical interference.
The prior art includes many filters mounted on portions of signal carrying circuits external to a circuit board. These prior art attempts have shared several significant deficiencies. In particular, most prior art electrical interference filters disposed at locations external to a circuit board have been complex and relatively expensive. Additionally, these complex prior art filters have not been well suited to long term use in a high vibration automotive environment, and are subject to failure in such an environment.
One such prior art filter is shown in U.S. Pat. No. 4,792,310 which issued to Hori et al. on Dec. 20, 1988. The electrical connector shown in U.S. Pat. No. 4,792,310 includes a shell made from an electrically conductive material. A pair of spaced apart insulating members are supported in parallel relationship within the conductive shell and function to support an array of parallel pin terminals. Each pin terminal passes through an annular capacitor which in turn is mounted to a radiating plate formed from a conductive material and connected to the electrically conductive shell. The annular capacitor elements shown in U.S. Pat. No. 4,792,310 comprise a substantially cylindrical inside electrode mounted to the pin terminal, a cylindrical dielectric mounted around the inside electrode and a cylindrical outside electrode mounted about the dielectric and soldered to the radiating plate. The small annular capacitor elements shown in U.S. Pat. No. 4,792,310 are expensive to manufacture and difficult to assemble. Additionally, the radiating plate shown in U.S. Pat. No. 4,792,310 would be subject to vibration in an automotive environment, with a substantial probability of eventual damage to the complex connections within or adjacent the capacitor elements.
U.S. Pat. No. 4,782,310 issued to Saburi et al. on Nov. 1, 1988 and shows a filter assembly identified for use in a vehicular environment. The filter assembly shown in U.S. Pat. No. 4,782,310 includes a plurality of overlapped thin insulation plates and electrode strips. The structure shown in U.S. Pat. No. 4,782,310 also would be extremely complex and expensive.
U.S. Pat. No. 4,733,328 issued to Blazej on Mar. 22, 1988 and is directed to a particular capacitor array and to a method of making the array. The method involves forming the capacitor directly in place on a grounding plate such that the capacitive element and the grounding plate are heat bonded to on another. The method proceeds by again effectively forming a conductive layer on the previously formed capacitor such that the conductive layer is heat-bonded to the capacitor. The formation of both the capacitor and the conductive layer involves the use of finely divided materials which are heat-sintered and thereby bonded to the adjacent layer of the capacitor array. Although the capacitor array described in U.S. Pat. No. 4,733,328 conceivably could have some application in an automotive environment, it appears to be an extremely expensive product to manufacture.
Another prior art filter assembly is shown in U.S. Pat. No. 4,772,221 which issued to Kozlof on Sept. 20, 1988. This connector filter includes an insulative capacitor housing ring having chip capacitors mounted therein. The insulative capacitor housing ring, the chip capacitors and an assembly of conductive washers are mounted to the connector housing with a lock washer and nut. This complex multicomponent assembly is not well suited for use in an automotive environment.
In view of the above, it is an object of the subject invention to provide a filter connector that is well suited for use in a high vibration automotive environment.
It is another object of the subject invention to provide an electrical connector that is capable of filtering electrical interference generated from or received by the leads extending to and from an electrical component.
An additional object of the subject invention is to provide a filter connector that can be manufactured relatively inexpensively, while still providing exceptional filtering abilities.